A magazine editor based in Chiang Mai faces up to five years in prison for sharing a student’s drawing on Facebook that depicted three ancient Thai kings wearing pollution masks ­­– created to raise awareness of the increasing levels of smog in the city.

Pim Kemasingki, editor of the English-language Chiang Mai CityLife, has been sued by the governor of Chiang Mai, who said the image breached the Computer-Related Crime Act (CCA) and that it was “disrespectful”, according to Reuters.

Pavin Chamniprasart, who reported the image in a letter to the police, said it mocks the three kings, but he added that his gripe was with the magazine and not the student.

“Let me insist that I’m not taking action against the kid,” Chamniprasart told Bangkok-based news site Khaosod English. “That person didn’t disseminate the picture. The wrongdoer is the website. Are we on the same page now?”

Kemasingki shared the picture, which she described as “pertinent and powerful”, to promote an anti-air pollution rally in the city. After a request by the governor, the event was cancelled, Reuters reported.

“For decades I’ve been promoting the city and loving it,” Kemasingki told Reuters. “So it’s quite unsettling that fighting for healthy air for my fellow citizens has turned into me besmirching the city.”

The CCA, which was amended in 2016, has been widely criticised by human rights groups that say it gives too much control to the government to restrict free speech.

“The adoption of the Computer-Related Crime Act drastically tightens the chokehold on online expression in Thailand,” said Brad Adams, executive director of Human Rights Watch’s Asia Division. “Hundreds of activists have been prosecuted since the May 2014 coup for exercising their freedom of expression online, and these latest amendments will make it even easier for the junta to punish its critics.”

Anyone convicted of breaking the law can receive a maximum five-year jail sentence, a fine of up to $2,700 or both.

An air quality report from the International Air Quality Monitoring website recorded “very unhealthy” levels of pollution in Chiang Mai last month. Particulate matter smaller than 2.5 microns reached as high as 203 micrograms per cubic metre of air in March; in Thailand, the daily standard for safe air is set at 50 micrograms, while the World Health Organisation’s daily standard is 25.

Thailand has one of the strictest lèse-majesté laws in the world, forbidding any form of perceived insult towards the highly respected royal family.

The student who drew the picture wrote on her Facebook page that she has lived in Chiang Mai for six years and had not intended to disrespect any of the three kings.

“I do not want to give my audience the wrong impression of my work patterns,” said the student, who goes by the name Music. “Some people might think that I am an ‘activist’ type of artist, when in reality… I’m just another teenage nerd who likes to draw cartoons.”

In a separate post, she said that it was “a shame that people are hurt by a picture and not the polluted air that they are breathing in”.